Plate clamp for printing machines



March 9, 1937. w STEPHENSQN PLATE CLAMP FOR PRINTING MACHINES sSheets-Sheet 1 Filed June 22, 1932 INVENTOR March 9, 1937. w. STEPHENSONPLATE CLAMP FOR PRINTING MACHINES Filed June 22, 1932 3 Sheets-Sheet 2March 9, 1937. w. STEPHENSON 2,072,909v

PLATE CLAMP FOR PRINTING MACHINES Filed June 22, 1932 3 Sheets-Sheet 3AS Q I wagi7 INVE/NTOR.

Patented Mar. 9, I937 PLATE CLAMP FOR PRINTING MACHINES WilliamStephenson, Rutherford, N. J., assignor, by mesne assignments, to R. Hoe& 00., Inc., New York, N. Y., a corporation of New York Application June22, 1932, Serial No. 618,651

Claims.

This invention relates to improvements in plate clamps adapted to securestereotype or other printing plates on the cylinders of a rotaryprinting machine.

A stereotype plate for a rotary printing machine is usually made withits curved edges beveled or tapered, and adapted to be engaged byundercut clips slidably mounted on the printing cylinder and forcedagainst the beveled edges of the plate by screws or other mechanicalmeans which are fixed in position while the cylinder is stationary.

With the present high speeds the centrifugal and other forces causedthereby, result in loosening the plates due to their indentation or wearso that with clips once fixed in place, the plates, which are ofcomparatively soft type-metal, become loose and sometimes forciblydisplaced resulting in accidents, damage and delay.

It is one of the objects of this invention to provide mechnical meansfor clamping the plates on the printing cylinder, and in addition tothis, strong spring pressure is used to keep the plate clips insufficiently forcible contact with the plates at all times when they areoperatively mounted and in use.

By means of this invention the stereotype plates are held securely inplace, and if their edges should be indented, for any reason, the

-consta nt spring pressure will cause the clips to follow them andcompensate for this. Stereotype plates, especially from differenttrimming machines, are of slightly different dimensions between theirclamping edges, but the mechanism .of this invention provides quick andready means for securing plates of different sizes and thus obviatesdelay or inconvenience on this account.

This invention provides a quick acting looking pin having a preferablyintegral crank pin, which is turned only about one-half a revolution tolook a plate in operative position, whereas the prior methodshereinbefore mentioned require a much longer time as 'they are dependenton the considerable travel of a screw or screws of small pitchnecessitating many rotations thereeasily movedv during the major part ofitsrotation, but as its movement continues itseccentric or crank pingradually deflects a powerful spring, and when the pin is locked in.operative position. the spring continues the pressure of the clip 5against the edge of the printing plate, regardless of whether the plateis indented or of slightly difierent width from the normal. 1

It will thus be seen that the mechanism of the present inventionprovides a speedy and simple movement for securing a plate on a printingcylinder, and the constant spring pressure is always working to maintainthe pressure of the clip against the plate under all operatingconditions notwithstanding the previous difllculties, connectedtherewith as heretofore explained.

It is also an object of'this invention to provide a plate clampingmechanism for printing machines of generally improved constructionwhereby the device is simple, durable and inexpensive to manufacture, aswell as convenient, practical, serviceable and efllcient in use.

With the foregoing and other objects in view, which will appear as thedescription proceeds, the invention resides in the combination andarrangement of parts and in the details of construction hereinafterdescribed and claimed, it being understood that various changes in theprecise embodiment of the invention herein disclosed may be made withinthe scope of what is claimed without departing from the spirit of theinvention. v

The preferred embodiment of the invention is illustrated in theaccompanyingdrawings, wherein:

Figure 1 is an end elevation of part of a printing cylinder with thisinvention applied thereto;

Figure 2 is a sectional plan on the line 2-2 of Figure 1 looking in thedirection of the arrow, and showing certain parts in-their clampingpositions; I

Figure 3 is a perspective view of the operating. stub shaft or lockingpin and. the eccentric or crank pin integral therewith;

Figure 4 is a perspective view of the sleeve or bushing in which thestubshaft or lockingpin is rotatably mounted;

Figure 5 is a perspective view of the operating wrench or lever withpart of its handle omitted for ease of illustration;

Figure 6 is a sectionalelevation on the'line 6-6 of Figure 1 looking inthe direction ofv the arrow, with the moving parts shown in retracted orinoperative positions;

Figure 7 is a view similar to Figure 6taken on the line of Figure 1looking in the direction of the arrow but with the moving parts inprojected or closed and operative positions;

Figure 8 is a cross section on the line 88 of Figure 2 looking in thedirection of the arrow, with the wrench in elevation, and

Figure 9 is an end elevation of part of a printing cylinder showing themannerof mounting the plate clip thereon.

Referring now to the characters of reference on the drawings Part of aprinting or form cylinder of a rotary printing machine is indicated asI, the plate clip slidably mounted therein is 2, the undercut plateengaging edge of which is I3.

It should be noted that the plate clip is arcuate and extends aroundalmost half of the plate cylinder and other similar clips, not shown,complete this part of the equipment to hold a plurality of platesthereon. l

Intermediate clipsare also used as customary to hold the inner edges ofthe plates. The armate clip l2 has a center slide portion l4 mounted inthe printing cylinder H in therabbets l5 and is retained by its tongues6, and, in addition to this, the clip l2 has similar end slides l4 andI4 the tongues 6 and I6" of which are mounted in the rabbets l5 and I5"respectively.

Part of the printing plate is indicated as IT and its beveled edgeagainst which the clip is adapted to engage is v The mechanism of thisinvention is preferably applied to the central portion and slide M ofthe arcuate clip |2as illustrated, and operates the entire clip thusrequiring a minimum of apparatus, time and laborin use. l

A front or clip plate I8 is provided and is fixedly secured on the endof the cylinder by the two socket head cap screws IS.

A spring box or container 24 has a lower or inner boss 25 as shown,which is internally threaded, and rotatably mounted therein is thethreaded adjusting screw 22 having a thrust collar as shown and isretained in the clip plate I8 by the bushing 2|,

This adjusting screw has a socket 23 in its head and can be turned byinserting the hexagon end 54 of the wrench 52 therein, thus adjustingthe positions of the parts connected therewith.

This adjustment is not used when the different printing plates are ofsubstantially uniform sizes, and it is only necessary to use thisadjustment to accommodate the mounting of plates of varying sizes.

The spring container 24 is made in the form of an open top rectangularbox as illustrated, with sides 26, front end 21 and rear or inner end28.

In this box is mounted a spring 29 preferably composed 'of a'pluralityof steel plates orleaves as shown, and in order that these shall bestfunction they have" an initial set or curvature, when free, opposite tothat illustrated in Figure 2. In other words, the spring 29 when free would have its convex side nearer to the center of the printing cylinderand its concave side nearer to the end of the cylinder, whereas when inuse and flexed as illustrated in Figures 2 and 7 the curvature isreversed as shown. 7

This provides the maximum spring pressure for operation with the minimumsize of spring and attachments.

A front bearing plate or abutment 3| is provided which bears against theends of the leaves of the spring and allows its deflection While on theother side of the spring a curved follower plate 32 is provided andadapted to press centrally of the spring. This is provided with wings orguides 33 adapted to slide along the spring box sides 25 and therebyinsure its correct axial movement.

Mounted in the spring box is a thrust member or locking plate 34 havinga cylindrical hole nearer to one end as shown. Rotatably mounted in theplate clip l2 and its center slide portion I4 is a locking member or pin35, having a cylindrical socket 35, and slots 31 connecting therewith,and it is also provided with recesses 38 and 39 to receive the end ofthe plunger pin 4|, which is adapted to be projected by the spring 42that is held in place by the slotted screw 43 as illustrated,

gral with the front end 21 of the spring box if preferred. Above thisand mounted on the plate clip I2 is the indicator 46, which when its endis flush with the indicator plate 45 as illustrated in Figure 7, showsthat the printing plate is properly 5 locked in position.

The locking pin is mounted in the bushing 41 which is provided with atop annular collar 48 having an annular space 49 below it and is furtherprovided with the slots 5| in its opposite sides.

These slots are adapted to permit the introduction and withdrawal of thelug wrench 52 having the opposed lugs 53 and the hexagon end 54.

The lug wrench can only be entered or withdrawn when the slots 5| and 31are in registry, which is the case when the plate clip is either in itssecurely locked or in its fully open position and so yieldingly held bythe locking pin 4| in the recess 39 or 38 respectively. The hexagon end54 of the wrench is adapted to fit in the socket 23 in the head of theadjusting bolt 22 so that one tool only is necessary to operate thedevices of this invention.

The mechanism when located as illustrated in the drawings forming parthereof is adapted for use at that end of the printing cylinder where itis shown on account of its convenience for the operator and the positionof the wrench for his easy manipulation.

This same mechanism is also used at the other end of the printingcylinder, and all that is necessary to do to adapt it to this use, is toturn the locking block 34 over or upside down.

This makes the clamping mechanisms right and left respectively, and eachis best adapted for easy use by the operator.

Having thus described the apparatus, a further description of itsfeatures, adaptability and mode of operation will now be presented:-

When the various parts of the mechanism are in the locations illustratedin Figure 6 they are in the fully retracted or unlocked positions andthe spring 29 exerts only its lesser initial pressure.

In this case, as may be seen in Figure 6, the locking pin 35 has beenrotated to move the plate clip |2 to the left and a-considerable gap orspace exists between the undercut surface I3 of the plate clip. ['2 andthe beveled edge l1 oi.

the printing plate II.

It should also be noted that at this time, the plunger pin 4| is seatedin the recess 38 of. the

'locking pin 35 to yieldingly hold the parts inpositions shown. Inaddition to this it will alsobeseen in Figure 6 that the indicator 46projects outwardly a considerable distance beyond the indicator plateand this is easily discovcred either by sight or touch, showing plainlythat the printing plate is fully unlocked.

When the locking mechanisms are in the po-' sitions shown in Figure 6 aprinting plate I! is manually located in the position shown, whereuponthe end of the wrench 52 is inserted in the socket 36 of the locking pin35 with its lugs 53 in the slots 31 after passing through the slots 5|'in the collar 48 of the bushing 41-.

This may be done by the same operator who has just placed the printingplate H in position on the cylinder II, with its other bevel. edgeagainst another clip, not shown.

The wrench handle is then turned about onehalf a revolution, until itslugs 53 register respectively with the other slots 5| in. the collar- 48of the bushing 4! whereupon the wrench can be withdrawn. It should benoted that the lug wrench can only be inserted when the cli-p I2 isunlocked or fully locked.

As the. locking pin 35 and the crank pin 44 are integral, and relativelyeccentric the partial rotation of the locking pin 35 will also partiallyrevolve the crank pin or eccentric 44. As the partial rotation andrevolution proceeds the plate clip I2 isproiected by the movement of thelocking pin 35, until its undercut edge I3- engages the beveled edge ll'of the printing plate l1, and simultaneously the eccentric 44, which isintegral with the locking pin tends to move toward the outer end of thecylinder.

As however this latter movement is resisted by the pressure of thespring 29 the first efiect is to project the undercut part l3 of theclip l2 against the bevel edge H of the printing plate l1, and afterthis is done the continuation of the movement bends the spring until itassumes the flexed shape shown in Figure 2 when the partsare inpositions shown in that figure and in Figure 7.

The arrangement and proportions of the parts are such that when inlocked position the axis .of the locking pin 35 is slightly past thelongitudinal center line through the axis of the eccentric 44 as may beseen in Figure 2', while the locking plate 34 is abutting the guide 33,.thus securely holding the printing plate in place as shown in Figure '7.At such a time the spring 29is compressed and constantly maintains thepressure of the clip l2 against the printing. plate I! and. even if thelatter should be indented by the forces due to its rotation or vibrationthe spring will cause the clip to follow up and continue its contactwith the plate with a substantially constant and predetermined force.The spring and other parts are so designed that this clamping force isalways of substantially the degree required or necessary to bestaccomplish the purpose.

The indicator 4G is so designed. and proportioned that when its bevelededge is flush with the indicator plate 45, as shown in Figure 7, theparts are in position to produce the desired clamping pressure, and theindicator may be both visually and tan-gibly inspected by the operatorto assure himself that the parts. are properly operative, with theprinting plates properly secured: so that it. is safe. to start therotation of the printing cylinder.

Should the edge of the bevel of the indicator 46 be not flush with theface of the indicator plate 45 as determined by sight if light is goodor by touch if in semi-darkness, the end 54 of the wrench 52 is insertedin the socket 23 of the adjusting bolt 22 and turned until the edge ofthe indicator is flush with the indicator plate 45, whereupon. the partsare positioned to produce the desired clamping pressure.

Should successive printing plates be of differentdimensionslongitudinally of the printing cylinder, the adjusting bolt 22may be turned to compensate for this,. in order to maintain the desiredclamping pressure.

The adjusting screw 22 or a longer one than shown can be used toaccommodate the mechanism; of this invention to clamp printing plates ofany sizesdependent on the widths of paper usedto produce" the printedproducts.

This adjusting screw 22 can also be used before or after the locking pin35 and its attachments are operated to quickly clamp a plate and this.can be done in a few seconds to properly accommodate printing plates ofany widths.

It should also be noted that the forward projection of the plate clip l2by the operation of the locking pin 35 and eccentric 44' is accomplishedspeedily in its first stages with little resistance, but, when the clipis about to engage with the plate, the leverage is greater, thusproviding increased force when it is necessary.

The size and strength of the spring 29 are determined, andthe pressureapplied to: the printingplatesthereby is also arranged by the designcient and substantially predetermined pressure is used.

By sodoing, the plates are held firmly and securely, but can not bedistorted or buckled as heretofore by undue pressure applied to aclamping screw or screws as sometimes occurs, with prior devices, due tohaste, ignorance or excessive force applied to the screw by theoperator.

By means of this invention all the plates on the printing cylinders canbe clamped with sub-- printing plate to be removed and replaced by'another one in the manner previously indicated.

As the locking pin and spring clamping arrangement in connectiontherewith can be operated ina few seconds by the quick turn of'a wrench,it can thus be seen that this mechanism is both a time and labor saveras compared to other methods and this of course is a desideratum.

What I claimis:

1. The combination with a printing cylinder having a printing platethereon, of a plate clip slidably mounted on the cylinder, a locking pinrotatably mounted in the clip, an eccentric forming. part of the lockingpin, a spring carried by the cylinder and adapted to be flexed by theeccentric, and means for rotating the locking pin and proportion. of theparts, so that only a suiliwhereby the plate clip is projected andengages the printing plate with a yielding pressure.

2. A printing cylinder, a plate clip slidably mounted thereon, a lockingpin mounted in the clip, a crank on said pin, means for rotating saidpin, thereby revolving the crank and reciprocating said pin and clip, abearing for said crank, and a spring connected to said cylinder, saidspring being flexed by the movement of said crank.

3. The combination with a printing cylinder having a printing platemounted thereon, of a plate clip adapted to engage the printing plate,said clip being slidably mounted on said cylinder, a locking pinrotatably mounted in said clip, an eccentric on said pin, a springconnected to said cylinder and said eccentric, and means for rotatingsaid pin to thereby project said clip, whereby said eccentric flexessaid spring, causing said clip to hold the printing plate with yieldingpressure.

4. A printing cylinder having a printing plate, a plate engaging clipslidably mounted thereon, a container mounted in said cylinder, a screwrotatably mounted in said cylinder and threaded in said containeradapted to adjust their relative positions, a spring in said container,a locking pin rotatably mounted in said clip, an eccentric on saidlocking pin, a spring carried in said container, a locking plate in saidcontainer in which said eccentric is rotatably mounted and adapted toflex said spring, and means for rotating said locking pin, whereby thespring is flexed as the plate clip is forwardly projected intoengagement with the printing plate.

5. A printing cylinder having a plurality of grooved slots extendinglongitudinally thereof, a printing plate with beveled clamping edgesmounted on said cylinder, an arcuate plate clip with an undercut edgeadapted to engage the printing plate, a plurality of slides on said clipmounted in the slots aforesaid, a locking pin rotatably mounted in saidclip and the central slide thereof, an eccentric on said pin, a bearingin which said eccentric is mounted, a spring associated with saidbearing, and means for rotating said pin adapted to project and retractsaid clip, whereby the spring is flexed by the eccentric during theforward projecting movement, thereby causing the clip to engage theprinting plate with a substantially predetermined but yielding springpressure.

6. A printing cylinder having a plurality of grooved slots extendinglongitudinally thereof, a printing plate with beveled clamping edgesmounted on said cylinder, an arcuate plate clip with an undercut edgeadapted to engage the printing plate, a plurality of slides on said clipmounted in the slots aforesaid, a locking pin rotatably mounted in saidclip and the central slide thereof, an eccentric on said pin, a bearingin which said eccentric is mounted, a spring associated with saidbearing, a screw rotatably secured to said cylinder and adapted tolongitudinally adjust said bearing, and means for rotating said pinadapted to project and retract said clip, whereby the spring is flexedby the eccentric during the forward projecting movement, thereby causingthe clip to engage the printing plate with a substantially predeterminedbut yielding spring pressure.

7. A printing cylinder having a plurality of grooved slots extendinglongitudinally thereof, a printing plate with beveled clamping edgesmounted on said cylinder, an arcuate plate clip with an undercut edgeadapted to engage the printing plate, a plurality of slides on said clipmounted in the slots aforesaid, a locking pin rotatably mounted in saidclip and the central slide thereof, means for securely locking said pinin its projected position and for yieldably looking it in its retractedposition, an eccentric on said pin, a container carrying a bearing inwhich said eccentric is mounted, a spring associated with said bearing,a screw rotatably secured to said cylinder and threaded in saidcontainer, and means for rotating said pin adapted to project andretract said clip, whereby the spring is flexed by the eccentric duringthe forward projecting movement, thereby causing the clip to engage theprinting plate with a substantially predetermined but yielding springpressure.

8. In a rotary printing machine, a printing cylinder, a plate clipslidable longitudinally of the cylinder, a rotatable locking membermovable with'the clip, an eccentric on the locking member,

a spring, an abutment for the spring adjustable longitudinally of thecylinder, and a thrust mem-- a thrust member engaging the eccentric, anabutment secured to the cylinder, and a multiple leaf spring operablyconnected between the thrust member and the abutment.

10. In a rotary printing machine, a printing cylinder, a plate clipslidable longitudinally of the cylinder, a rotatablelocking membermovable with the clip, an eccentric on the locking member, a thrustmember engaging the eccentric, an abutment secured to the cylinder andadjustable longitudinally thereof, and a multiple leaf spring operablyconnected between the thrust member and the abutment.

11. In a mechanism for clamping stereotype plates to a form cylinder, aplate clip longitudinally movable on said form cylinder, a containerpositioned within said cylinder, a laminated spring within saidcontainer, a slidable thrust member engaged by said spring, and manuallyactuated means engaging said plate clip and thrust member to projectsaid plate clip and simultaneously fiex said spring, whereby a yieldingpressure is exerted upon the plate'clip when projected into engagementwith a plate.

12. The combination with a printing cylinder having a printing platethereon, of a clip longitudinally slidable on the cylinder, means forprojecting the clip to engage and lock said printing plate on theprinting cylinder, an indicator secured to the end of the plate clip andlongitudinally movable therewith and an indicator plate, relativelystationary with respect to said clip, cooperating with said indicator todetermine by their relative positions the correctness of the clipengagement with said printing plate.

13. In a mechanism for clamping stereotype I 2,072,909 yielding springpressed engagement therewith by the cooperative action between theeccentric and spring.

14. In a mechanism for clamping stereotype plates to a form cylinder, aplate clip longitudinally movable on said form cylinder, a containerarranged within said cylinder, means to adjust the containerlongitudinally of the cylinder, a spring within said container, a thrustmember within said container, a manually rotatable looking pinpositioned within said clip, and an eccentric portion on said lockingpin positioned within said thrust member, whereby upon rotation of thelocking pin, the thrust member is moved backward by the eccentricagainst the pressure of the spring and the plate clip is moved forwardinto yieldable engagement with the plate.

15. In a plate clamping mechanism for a printing machine, a plateengaging member slidable into and out of plate clamping position,resilient means operatively associated with said member and arranged tourge the same into plate clamping position, means carried by said plateclamping member and adapted to move it toward and away from plateclamping position, and means to adjust said member relatively to theplate when in plate clamping position.

16. In a plate clamping mechanism for a printing machine, a plateengaging member slidable into and out of plate clamping position,resilient means operatively associated with said member and arranged tourge the same into plate clamping position, means carried by said plateengaging member to move said plate clamping member toward and away fromplate clamping position, means to adjust said member relatively to theplate when in plate clamping position, and means to indicate the amountof such adjusting movement.

17. In a plate clamping mechanism for a printing machine, a plateengaging member slidable into and out of plate clamping position,

resilient means operatively associated with said member and arranged tourge the same into plate clamping position, means carried by said plateclamping member and adapted to move it toward and away from plateclamping position, and means to increase and decrease the tension ofsaid resilient means when said member is in plate clamping position.

18. In a mechanism for clamping plates to a cylinder of a printingmachine, a plate clamping member longitudinally movable relatively tosaid cylinder, a part disposed in said cylinder and movable relativelyto said member, a spring mounted in said cylinder in engagement withsaid part, and operable means in said cylinder in operative engagementwith said part through said spring and in engagement with said member tomove said member into and out of plate clamping position.

19. In a device for clamping a plate on a cylinder of a printingmachine, a plate clip slidably mounted on the cylinder, a resilientmember, a part rotatably secured to said plate clip, and mechanismaffected by said resilient means to press said plate clip against theplate and cooperating with said part upon rotation thereof to move saidplate clip toward and away from the plate.

20. In a mechanism for clamping plates to a cylinder, a plate clampingclip longitudinally movable relatively to said cylinder, spring pressedmeans in said cylinder, a member rotatably mounted to and longitudinallymovable with said clip, a part of said member being eccentric theretoand in operable association with said spring pressed means, and means torotate said member in one direction, to move said clip and said springpressed means in opposite directions, to clamp the plate to saidcylinder, and to compress said compressible means.

WILLIAM STEPHENSON.

